The present invention relates to an air-conditioning apparatus with a refrigerant circuit. This invention is directed more specifically to providing means for prevention of harmful effects due to refrigerant leakage.
Air-conditioning apparatus that perform a refrigerating cycle by refrigerant circulation in a refrigerant circuit have long been known. Besides, there is known another air-conditioning apparatus of the type that its every constitutional equipment such as a refrigerant circuit, a fan, and the like is housed within an outdoor casing and the outdoor casing and an indoor space are connected together by a duct for supplying conditioned-air into the room. An example of such a type of air-conditioning apparatus is an air-conditioning apparatus of the so-called roof top type. In that air-conditioning apparatus, its casing is placed on a roof of for example a house and duct connected to a room.
Since CFC, a substance which has been used as a refrigerant for air conditioners and refrigerators, destroys the Earth""s ozone layer, there have been attempts to replace CFC refrigerants with ozone-friendly refrigerants. These CFC replacements are HFC substances such as R32, R152a, and the like. However, these substances are slightly flammable. If such a flammable substance is employed as a refrigerant for air-conditioning apparatus with an outdoor refrigerant circuit and if there occurs refrigerant leakage from the refrigerant circuit, this introduces the danger that leaking refrigerant flows into a room by way of a duct. Such refrigerant leakage may cause serious hazards. For example if leaking refrigerant is ignited in the room, this may cause a fire.
On the other hand, R407C and R410A, which are combined refrigerants containing R32, have been proposed. These combined refrigerants contain R125 which is an ignition suppressant and their flammability is lower in comparison with sole R32. However, because of the mixing of R125, the global warming potential (GWP) (the ratio with respect to CO2) becomes relatively high. More specifically, the GWPs of R407C, R410A, R404A, and R22 are 1530,1730, 3260, and 1500, respectively. On the other hand, since R32 and R152a have molecules that contain a relatively larger amount of hydrogen, they are easily decomposed in the atmosphere and have low GWP. Because of this, when taking into consideration the GWP, it is preferable that R32 or the like be used alone as a refrigerant.
As the aforesaid replacement for CFC, hydrocarbon refrigerants such as propane and butane have been known, but these hydrocarbon refrigerants are highly flammable. Therefore, if a refrigerant of the above flammable type is used in the foregoing air-conditioning apparatus, this may cause a fire hazard not only when the refrigerant leaks and flows into a room, but also even when the leaking refrigerant stays within the casing. That is, since these refrigerants are highly flammable, there is the danger that they are ignited by a slight spark occurring at a relay contact point in an electric system of the air-conditioning apparatus, thereby causing a fire hazard.
Further, even when a typical R22 substance or the like is used as a refrigerant, the possibility of accidents such as suffocation due to a lack of oxygen exists if leaking refrigerant flows into a room.
Bearing in mind the above-described problems, the present invention was made. Accordingly, an object of the present invention is to provide means for preventing the occurrence of harmful effects due to refrigerant leakage in air-conditioning apparatus with an outdoor refrigerant circuit.
In the present invention, leaking refrigerant from the refrigerant circuit is assuredly discharged into the open air.
The present invention provides a first solution means intended for an air-conditioning apparatus including a refrigerant circuit (20) charged with refrigerant. In this air-conditioning apparatus, a utilization side air passageway (35) in which a utilization side heat exchanger (24) for the refrigerant circuit (20) is disposed is divided into zones, the utilization side air passageway (35) being in communication with the inside of a room. In addition, an opening portion (40), which opens to the utilization side air passageway (35) to allow the utilization side air passageway (35) to communicate with the outside of the room so that refrigerant leaking from the refrigerant circuit (20) into the utilization side air passageway (35) is at least discharged from the opening portion (40) to outside the room.
The present invention provides a second solution means intended for an air-conditioning apparatus comprising an outdoor casing (11) for housing therein a refrigerant circuit (20) charged with refrigerant. In this air-conditioning apparatus, a utilization side air passageway (35) in which a utilization side heat exchanger (24) for the refrigerant circuit (20) is disposed and a heat source side air passageway (31) in which a heat source side heat exchanger (22) for the refrigerant circuit (20) is disposed are formed in the casing (11), these passageways (35) and (31) being in communication with the inside and the outside of a room, respectively. In addition, an opening portion (40) allowing the utilization side air passageway (35) to communicate with the outside of the casing (11) is formed in the casing (11).
The present invention provides a third solution means according to the first or second solution means in which the refrigerant of the refrigerant circuit (20) comprises a substance whose atmospheric specific gravity is greater than that of air and the opening portion (40) is so formed as to open to a lower portion of the utilization side air passageway (35).
The present invention provides a fourth solution means according to the third solution means wherein the opening portion (40) is so formed as to open to the utilization side air passageway (35) at a level lower than one-third of the overall height of the utilization side air passageway (35) from the bottom of the utilization side air passageway (35).
The present invention provides a fifth solution means according to the first or second solution means wherein the refrigerant of the refrigerant circuit (20) comprises a substance whose atmospheric specific gravity is smaller than that of air and the opening portion (40) is so formed as to open to an upper portion of the utilization side air passageway (35).
The present invention provides a sixth solution means according to the fifth solution means wherein the opening portion (40) is so formed as to open at a level higher than two-thirds of the overall height of the utilization side air passageway (35) from the bottom of the utilization side air passageway (35).
The present invention provides a seventh solution means according to the second solution means wherein the refrigerant of the refrigerant circuit (20) comprises a substance whose atmospheric specific gravity is greater than that of air, wherein an air suction opening (38) is formed in a lateral portion of the casing (11), thereby allowing the utilization side air passageway (35) to communicate with the inside of the room through a duct (17) connected to the air suction opening (38), and wherein the opening portion (40) is so formed as to open to the utilization side air passageway (35) at a level lower than the uppermost portion of the air suction opening (38).
The present invention provides an eighth solution means according to the second solution means wherein the refrigerant of the refrigerant circuit (20) comprises a substance whose atmospheric specific gravity is smaller than that of air, wherein an air suction opening (38) is formed in a lateral portion of the casing (11), thereby allowing the utilization side air passageway (35) to communicate with the inside of the room through a duct (17) connected to the air suction opening (38), and wherein the opening portion (40) is so formed as to open to the utilization side air passageway (35) at a level higher than the lowermost portion of the air suction opening (38).
The present invention provides a ninth solution means according to any one of the first to eighth solution means wherein the opening portion (40) is so formed as to open to both upstream and downstream sides of the utilization side heat exchanger (24) in the utilization side air passageway (35).
The present invention provides a tenth solution means according to the second solution means wherein an air suction opening (38) is formed in the casing (11), thereby allowing the utilization side air passageway (35) to communicate with the inside of the room through a duct (17) connected to the air suction opening (38) and wherein a baffle plate (41) is positioned in the air suction opening (38) so that refrigerant leaking from the refrigerant circuit (20) into the utilization side air passageway (35) is prevented from flowing into the inside of the room.
The present invention provides an eleventh solution means according to the second solution means wherein the refrigerant of the refrigerant circuit (20) comprises a substance whose atmospheric specific gravity is greater than that of air, wherein the utilization side air passageway (35) communicates with the inside of the room through a duct (17) connected to a bottom portion of the casing (11), and wherein the duct 17 is connected to the casing (11) so that one end of the duct (17) projects into the utilization side air passageway (35).
The present invention provides a twelfth solution means according to the second solution means wherein the utilization side air passageway (35) in which a utilization side blower means (12) is disposed is zoned into an upstream passageway (36) on the upstream side of the utilization side blower means (12) and a downstream passageway (37) on the downstream side of the utilization side blower means (12), wherein the refrigerant circuit (20) is so arranged in the upstream passageway (36) and in the heat source side air passageway (31) as to detour the downstream passageway (37), and wherein the opening portion (40) is so formed as to allow the upstream passageway (36) of the utilization side air passageway (35) to communicate with the outside of the casing (11).
The present invention provides a thirteenth solution means according to the first or second solution means wherein a detection means for detecting the presence or absence of a refrigerant leak from the refrigerant circuit (20), an exhaust blower means for discharging refrigerant in the utilization side air passageway (35) from the opening portion (40), and a control means for performing control so that, upon detection of a refrigerant leak by the detection means, the blower means is brought into operation, are provided.
The present invention provides a fourteenth solution means intended for an air-conditioning apparatus comprising an outdoor casing (11) for housing a refrigerant circuit (20) charged with refrigerant. In this air-conditioning apparatus, a utilization side air passageway (35) in which a utilization side heat exchanger (24) for the refrigerant circuit (20) is disposed and a heat source side air passageway (31) in which a heat source side heat exchanger (22) for the refrigerant circuit (20) is disposed are formed in the casing (11), these passageways (35) and (31) being in communication with the inside and the outside of a room, respectively. In addition, the air-conditioning apparatus further comprises a heat source side blower means (13) disposed in the heat source side air passageway (31), a detection means for detecting the presence or absence of a refrigerant leak from the refrigerant circuit (20), a switching means for performing switching so that the connection of the utilization side air passageway (35) and the heat source side air passageway (31) switches between a communicated state and a disconnected state, and a control means for performing control so that, upon detection of a refrigerant leak by the detection means, the utilization side air passageway (35) and the heat source side air passageway (31) are brought into communication with each other and the heat source side blower means (13) is brought into operation.
The present invention provides a fifteenth solution means intended for an air-conditioning apparatus comprising an outdoor casing (11) for housing a refrigerant circuit (20) charged with flammable refrigerant. In this air-conditioning apparatus, a utilization side air passageway (35) in which a utilization side heat exchanger (24) for the refrigerant circuit (20) is disposed and a heat source side air passageway (31) in which a heat source side heat exchanger (22) for the refrigerant circuit (20) is disposed are formed in the casing (11), these passageways (35) and (31) being in communication with the inside and the outside of a room, respectively. In addition, the air-conditioning apparatus further comprises a heat source side blower means (13) disposed in the heat source side air passageway (31), a detection means for detecting the presence or absence of a refrigerant leak from the refrigerant circuit (20), and a control means for performing control so that, upon detection of a refrigerant leak by the detection means, the heat source side blower means (13) is brought into operation.
The present invention provides a sixteenth solution means according to any one of the first to fourteenth solution means wherein the refrigerant of the refrigerant circuit (20) comprises a flammable substance.
In the first solution means, refrigerant circulates in the refrigerant circuit (20), whereby a refrigerating cycle is performed. Indoor air is drawn into the utilization side air passageway (35). The drawn air is cooled by heat exchange with refrigerant in the utilization side heat exchanger (24) and thereafter returned to the room. An arrangement may be made in which a four-way selector valve or the like is provided in the refrigerant circuit (20) to make the direction of refrigerant circulation reversible to permit heat pump operation.
If there occurs refrigerant leakage from the refrigerant circuit (20) during shutdown, leaking refrigerant will flow into the utilization side air passageway (35). However, the leaking refrigerant, after passing through the opening portion (40), is purged from the utilization side air passageway (35) to outside the room. At that time, it may be arranged such that leaking refrigerant is purged from the opening portion (40) automatically or forcedly. Therefore, the leaking refrigerant will not flow into the room.
In the second solution means, refrigerant circulates in the refrigerant circuit (20), whereby a refrigerating cycle is performed. An arrangement may be made in which a four-way selector valve or the like is provided in the refrigerant circuit (20) to make the direction of refrigerant circulation reversible to permit heat pump operation. Indoor air is drawn into the utilization side air passageway (35). The drawn air is cooled by heat exchange with refrigerant in the utilization side heat exchanger (24) and thereafter returned to the room. On the other hand, outdoor air is drawn into the heat source side air passageway (31). The drawn air is cooled by heat exchange with refrigerant in the heat source side heat exchanger (22) and thereafter returned to outside the room. In this way, air-conditioning operation of the air-conditioning apparatus is performed.
If there occurs refrigerant leakage from the refrigerant circuit (20) during shutdown, leaking refrigerant will flow into the utilization side air passageway (35). However, the leaking refrigerant, after passing through the opening portion (40) formed in the casing (11), is purged to outside the casing (11). At that time, it may be arranged such that leaking refrigerant is purged from the opening portion (40) automatically or forcedly. Therefore, the leaking refrigerant will neither stay in the casing (11) nor flow into the room.
In the third solution means, since the specific gravity of the refrigerant used is greater than that of air, leaking refrigerant from the refrigerant circuit (20) stays in the lower area of the utilization side air passageway (35). However, since the opening portion (40) opens to a lower portion of the utilization side air passageway (35), the leaking refrigerant is automatically purged from the opening portion (40) to outside the room by gravity.
In the fourth solution means, in the utilization side air passage way (35) the opening portion (40) opens to the utilization side air passageway (35) at a level between the bottom of the utilization side air passageway (35) and a position situated above the bottom of the utilization side air passageway (35) by one-third of the overall height of the utilization side air passageway (35).
In the fifth solution means, since the specific gravity of the refrigerant used is smaller than that of air, leaking refrigerant will stay in the upper area of the utilization side air passageway (35). However, since the opening portion (40) opens to an upper portion of the utilization side air passageway (35), the leaking refrigerant is automatically purged from the opening portion (40) to outside the room by buoyancy.
In the sixth solution means, the opening portion (40) opens to the utilization side air passage way (35) at a level higher than two-thirds of the overall height of the utilization side air passageway (35) from the bottom thereof.
In the seventh or eighth solution means, the air suction opening (38) is formed in a lateral portion of the casing (11) and the duct (17) is connected to the air suction opening (38). The duct (17) extends into the room, and the utilization side air passageway (35) is brought into communication with an indoor space through the duct (17).
Further, in the seventh solution means, since the specific gravity of the refrigerant used is greater than that of air, leaking refrigerant from the refrigerant circuit (20) travels downwardly from the refrigerant circuit (20). The opening portion (40) opens to the utilization side air passageway (35) at a level lower than the uppermost portion of the air suction opening (38). As a result of such arrangement, the leaking refrigerant from the refrigerant circuit (20) will neither stay in the duct (17) nor flow into the room through the duct (17). That is, the leaking refrigerant is purged to outside the casing (11) from the opening portion (40).
Further, in the eighth solution means, since the specific gravity of the refrigerant used is smaller than that of air, leaking refrigerant from the refrigerant circuit (20) travels upwardly from the refrigerant circuit (20). The opening portion (40) opens to the utilization side air passageway (35) at a level higher than the lowermost portion of the air suction opening (38). As a result of such arrangement, the leaking refrigerant from the refrigerant circuit (20) will neither stay within the duct (17) nor flow into the room through the duct (17). That is, the leaking refrigerant is purged to outside the casing (11) from the opening portion (40).
In the ninth solution means, the opening portion (40) opens to both upstream and downstream sides of the utilization side heat exchanger (24) in the utilization side air passageway (35).
In the tenth solution means, the air suction opening (38) is formed in the casing (11), and the duct (17) is connected to the air suction opening (38). The duct (17) extends to the room and the utilization side air passageway (35) is brought into communication with an indoor space through the duct (17). The specified baffle plate (41) is positioned in the air suction opening (38). Because of such arrangement, leaking refrigerant from the refrigerant circuit (20) is obstructed by the baffle plate (41), in other words, the leaking refrigerant will not flow, from the air suction opening (38), into the room by way of the duct (17). That is, the leaking refrigerant is purged from the opening portion (40) to outside the casing (11).
In the eleventh solution means, the specific gravity of the refrigerant used is greater than that of air, so that leaking refrigerant from the refrigerant circuit (20) travels downwardly from the refrigerant circuit (20) and stays also in the lower area of the utilization side air passageway (35). The duct (17) is connected to a bottom portion of the casing (11) with one end thereof projecting into the utilization side air passageway (35). Because of such arrangement, the refrigerant staying in the bottom area of the utilization side air passageway (35) will flow neither into the duct (17) nor into the room through the duct (17).
In the twelfth solution means, the utilization side air passageway (35) is zoned into the upstream passageway (36) on the upstream side of the utilization side blower means (12) and the downstream passageway (37) on the downstream side. The refrigerant circuit (20) is so arranged as to detour the downstream passageway (37), in other words, the refrigerant circuit (20) is arranged only in the upstream passageway (36) and heat source side air passageway (31). If there occurs refrigerant leakage from the refrigerant circuit (20), leaking refrigerant flows only into the passageways (36) and (31). The leaking refrigerant will not flow into the downstream passageway (37), unless the utilization side blower means (12) is brought into operation. Because of this, the leaking refrigerant will not flow into the room from the downstream passageway (37). Further, since the heat source side air passageway (31) is in communication with the outside of the room, refrigerant flowing into the heat source side air passageway (31) is discharged to outside the casing (11), whereas refrigerant flowing into the upstream passageway (36) is discharged from the opening portion (40) to outside the casing (11).
In the thirteenth solution means, when there occurs refrigerant leakage from the refrigerant circuit (20), such a refrigerant leak is detected by the detection means. The control means performs control so that upon detection of a refrigerant leak by the detection means the exhaust blower means is brought into operation. Because of this, the leaking refrigerant is discharged from the opening portion (40) to outside the room.
In the fourteenth solution means, cooling operation of the air-conditioning apparatus is performed in the same way as the second solution means. At that time, outdoor air is drawn into the heat source side air passageway (31) by the operation of the heat source side blower means (13). The drawn air, after passing through the heat source side heat exchanger (22), is discharged. If the detection means detects refrigerant leakage during cooling operation shutdown, the control means performs control so that the switching means (43) switches and the heat source side blower means (13) is brought into operation. By virtue of such switching by the switching means (43), the utilization side air passageway (35) and the heat source side air passageway (31) are brought into communication with each other. The heat source side blower means (13) is brought into operation in such a communicated state, whereby refrigerant leaking from the refrigerant circuit (20) into the utilization side air passageway (35) is drawn by the heat source side blower means (13) and discharged to outside the casing (11).
In the fifteenth solution means, cooling operation of the air-conditioning apparatus is performed in the same way as the second solution means. At that time, outdoor air is drawn into the heat source side air passageway (31) by the operation of the heat source side blower means (13). The drawn air, after passing through the heat source side heat exchanger (22), is discharged. The refrigerant of the refrigerant circuit (20) comprises a flammable substance. There are example flammable substances which can be used as the refrigerant, namely, HFC substances such as R332 and R152a, combined refrigerants containing R32 et cetera, and hydrocarbons such as propane, butane, and isobutane. If the detection means detects a refrigerant leak during cooling operation shutdown, the heat source side blower means (13) is brought into operation. Because of this, refrigerant leaking from the refrigerant circuit (20) into the heat source side air passageway (31) is drawn by the heat source side blower means (13) and discharged to outside the casing (11).
In the sixteenth solution means, the refrigerant of the refrigerant circuit (20) comprises a flammable substance. There are example flammable substances which can be used as the refrigerant, namely, HFC substances such as R332 and R152a, combined refrigerants containing R32 et cetera, and hydrocarbons such as propane, butane, and isobutane.
In the fifteenth solution means, cooling operation of the air-conditioning apparatus is performed in the same way as the second solution means. At that time, outdoor air is drawn into the heat source side air passageway (31) by the operation of the heat source side blower means (13). The drawn air, after passing through the heat source side heat exchanger (22), is discharged. The refrigerant of the refrigerant circuit (20) comprises a flammable substance. There are example flammable substances which can be used as the refrigerant, namely, HFC substances such as R32 and R152a, combined refrigerants containing R32 et cetera, and hydrocarbons such as propane, butane, and isobutane. If the detection means detects a refrigerant leak during cooling operation shutdown, the heat source side blower means (13) is brought into operation. Because of this, refrigerant leaking from the refrigerant circuit (20) into the heat source side air passageway (31) is drawn by the heat source side blower means (13) and discharged to outside the casing (11).
In the sixteenth solution means, the refrigerant of the refrigerant circuit (20) comprises a flammable substance. There are example flammable substances which can be used as the refrigerant, namely, HFC substances such as R32 and R152a, combined refrigerants containing R32 et cetera, and hydrocarbon such as propane, butane, and isobutane.
As a result, even when flammable substances are used as a refrigerant for the refrigerant circuit (20), it is possible to prevent the refrigerant concentration from increasing in the air (in other words, the refrigerant is prevented from igniting) and it is also possible to avoid serious accidents such as a fire due to refrigerant leakage. And, it is possible to use, as a refrigerant, a substance of low GWP which does not destroy the Earth""s ozone layer (although it exhibits flammability), while maintaining safety, and it is possible to suppress adverse global environmental effects.
Particularly, in accordance with the third to ninth solution means, since it is arranged such that the opening portion (40) opens to the utilization side air passageway (35) at a given level, leaking refrigerant from the refrigerant circuit (20) is automatically discharged from the opening portion (40) to outside the casing (11), thereby making it possible to prevent the leaking refrigerant from flowing into the room. As a result, the discharging of leaking refrigerant can be performed by providing only the opening portion (40), thereby making it possible to assuredly avoid the occurrence of accidents due to refrigerant leakage while keeping the structure simple.
Further, in accordance with the tenth to twelfth solution means, it is possible to assuredly prevent leaking refrigerant from the refrigerant circuit (20) from flowing into the room by the provision of the baffle plate (41), the structure of the duct (17), or the structure of the utilization side air passageway (35) and the arrangement of the refrigerant circuit (20). Because of this, it is possible to assuredly avoid the occurrence of accidents due to refrigerant leakage.
Furthermore, in accordance with the thirteenth solution means, leaking refrigerant from the opening portion (40) is forcedly discharged to outside the room by the exhaust blower means, so that it is possible to assuredly discharge leaking refrigerant to outside the casing (11), even during air-conditioning operation.
Further, in accordance with the fourteenth solution means, it is possible to forcedly discharge leaking refrigerant to outside the casing (11) by appropriating the heat source side blower means (13) of the heat source side air passageway (31).
Furthermore, in accordance with the fifteenth solution means, it is possible to assuredly discharge refrigerant leaking from the refrigerant circuit (20) to the heat source side air passageway (31), to outside the casing (11). The present solution means is particularly effective for cases in which highly flammable substances such as propane are used as a refrigerant for the refrigerant circuit (20). That is, since the heat source side air passageway (31) is in communication with the outside of the room, leaking refrigerant is unlikely to stay in the passageway (31); however, there still exists the possibility that such a highly flammable substance becomes ignited even when its amount is very small. On the other hand, in accordance with the present solution means, it is possible to assuredly prevent the occurrence of accidents such as a fire because leaking refrigerant is discharged out of the casing (11) by bringing the heat source side blower means (13) into operation.